The present invention relates to a unique form of expandable metal foil and to expanded metal nets made therefrom. The invention also relates to methods and apparatus for producing the said products, and to uses thereof, particularly in the extinguishing of fires and the prevention of explosions.
Surface fires, such as grassland and forest fires, as well as fires on the surface of water and on the surface of fuels in fuel tanks, are a continuing threat to life and property throughout the world. Over the years, numerous methods for combating such fires have been developed. The use of water, foams, chemicals and other quenching materials are well known.
It is also known to use blankets, mats, nets and other sheet-like materials to smother surface fires. However, these are heavy, bulky materials, and their use in widespread surface fires extending over thousands of acres of land or water, are subject to obvious limitations. Firefighting methods today are still limited to the steps of containing the fire as much as possible until it burns out or until changing weather conditions no longer support the burning. There is a need for a more efficient, inexpensive means for extinguishing fires which extend over wide surface areas.
There is also a need for more effective ways of preventing explosions in containers for fuels or other flammable substances. Containers such as fuel depots, liquid petroleum gas tanks, airplanes, ships, transport tankers, pipelines, and the like, are at risk from explosion caused by overheating, static electricity build up, mechanical impacts, etc. In addition to precautionary measures such as avoiding the above causes, a more recent approach to the problem has involved placing in the container a quantity of filling material in the form of a honeycomb shaped metal net--either in sheets or crumpled into balls. The theory of such approach is that the metal net promotes heat conduction and avoids static electricity build up, and thus reduces the risk of explosion. Although the approach has merit, there is nevertheless a substantial need for improvement, mainly because of deficiencies in the physical characteristics of the metal nets and balls, and also because of inefficiencies in the methods and apparatuses for producing such materials.
It is an object of the present invention to provide a product which is substantially more effective than known products, not only in the extinguishing of surface fires but also in the prevention of explosions in fuel tanks and the like.
It is a further object of the invention to provide a fire extinguishing product which can be transported to the site of a surface fire in compact, semi-manufactured form and then stretched to its fully manufactured form as it is applied to the surface of the fire over an extended area.
It is another object of the invention to provide a product for filling into containers for fuel and other flammable materials to provide a highly superior anti-explosive protection.
It is a still further object of the invention to provide unique methods and apparatus for production of the said new product.
Other objects and advantages will become apparent as the specification proceeds.